Over the years, several Boeing 747 aircraft that formerly flew passengers have found a second life at NASA. Two of those 747s found themselves piggybacking NASA's space shuttles around North America. While it wasn't unknown for the space shuttles to be transported short distances by road, these two 747s did much of the long-distance heavy lifting.

Between 1981 and 2011, NASA flew 135 space shuttle missions. The final flight was in July 2011 when Atlantis successfully landed at Kennedy Space Center in Florida. High ongoing maintenance costs and economic rationalization were behind the shuttle's demise. However, the space shuttle was also becoming dated, and the Columbia disaster in 2003 caused significant reputational damage.

Two Boeing 747s used to piggyback NASA's space shuttles

For a good portion of those 30 years, NASA's specially modified 747s shuttled the space shuttles around the United States. Officially, NASA named the planes Shuttle Carrier Aircraft (or SCAs). While the two SCAs were owned and under the operational control of NASA's Johnson Space Center at Houston, the primary space shuttle launch pad was at Kennedy Space Center in Florida. The space shuttle's secondary landing site was at Edwards Air Force Base in California. All up, the two 747s flew 87 post landing ferry flights for NASA, giving the travel-weary space shuttle a lift. That's in addition to hundreds of other flights, ferrying the space shuttle here and there.

Minus fuel, NASA says an empty space shuttle weighs just under 75 tonnes. But with four Pratt & Whitney JT9D-7J gas turbine engines, each producing 48,600 lb of thrust, the space shuttle's weight wasn't an issue for the 747s.

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The two NASA 747s flying in formation over California. Photo: NASA

NASA's two 747s used to ferry space shuttles were tagged as NASA 905 and NASA 911. NASA 905, a Boeing 747-123 model built in 1970, did the bulk of the heavy lifting. It operated 70 of the 87 ferry missions during the shuttle program's operational phase, including 46 of the 54 post-mission ferry flights from Edwards to the Kennedy Space Center. After the space shuttles were retired, NASA 905 flew three ferry flights to deliver the shuttles Discovery, Enterprise, and Endeavour to museums where they are currently on display.

The second 747, NASA 911, started to fly for NASA in 1989. It flew 17 of the post-shuttle-landing ferry flights from Edwards to Kennedy Space Center. This plane is a modified Boeing 747-100SR-46 that formerly flew for Japan Air Lines.

Former passenger planes get modified

NASA had to make modifications to both aircraft before they could piggyback the space shuttles. In a nutshell, those modifications were;

  • Three struts with associated interior structural strengthening attached to the top of the fuselage (two aft, one forward) on which the orbiter is attached;
  • Two additional vertical stabilizers, one on each end of the standard horizontal stabilizer, to enhance directional stability;
  • Removal of all interior furnishings and equipment aft of the forward No. 1 doors; and
  • Instrumentation used by SCA flight crews and engineers to monitor orbiter electrical loads during the ferry flights and also during pre and post-ferry flight operations was added.

Large gantry-like cranes loaded the space shuttles onto the modified 747s.

Over 1983 and 1984, NASA 905 took one of the space shuttles, Enterprise, on a world tour. visiting France, West Germany, Italy, the United Kingdom, and Canada. Over those two years, the 747 also piggybacked Enterprise to various sites around the United States, including to the 1984 World Expo in Louisana, where it became a star attraction.

Both NASA SCA 747s retired following the end of the space shuttle program. For a while, they flew the surviving shuttles to their permanent display locations around the United States. Then the 747s went on display themselves. Today, you can see NASA 911 at the Joe Davies Heritage Airpark in Palmdale, California. As for the mighty NASA 905, that's on display at the Johnson Space Center's visitor center in Houston.

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